The Array Core provides arrays and associated services for analysis of DMA copy number variation (array CGH) as well as custom array printing. Array CGH: The arrays for CGH analysis consist of BAG clones distributed over the human^and mouse genomes. These arrays allow reliable detection of single copy changes from diploid as well as high-level amplifications. The BAG arrays produce good data from formalin fixed-paraffin embedded samples and thus allow studies that are not currently possible with arrays from other sources. The core will continue to offer BAG arrays with -1-1.5 Mb resolution for human and murine analysis, and a 32,000 BAG whole human genome tiling array. The latter allows resolution to a fraction of the length of a BAG, or well below 100kb. In addition to these standard arrays, the Core will print custom arrays for individual projects, provide instruction on use of the BAG arrays it offers (DMA isolation, labeling, hybridization, imaging and analysis), and consult on interpretation of data. It will also continue to offer a full array processing service, receiving DNA from investigators and returning data. Instrumentation: The Core operates three array imaging systems, an Axon 4000B laser scanner, a custom built 1M pixel CCD camera system, and a custom built 4M pixel CCD imaging system. The Core also operates a custom, high-speed array printer. Other equipment includes a liquid handling robot and a fully stocked laboratory for array processing and preparation of printing solutions.